The present invention related to an inductance element used for power supply units for electronic equipment, and the like.
In recent years, to enhance the mounting density of circuit boards for miniaturizing electronic equipment, inductance elements as electronic parts have been required to be miniaturized and thinned, and further to have an electric performance allowed to carry a large current while being miniaturized and thinned.
FIG. 10 shows the structure of a related art inductance element, in which a drum core 20 around which a coil 21 is wound is fixed on a base 22, and winding terminals 21a of the coil are connected to terminal boards 23 mounted on the base 22. Japanese Utility Model Laid-open Nos. Sho 64-39612 and Hei 5-95010 disclose inductance elements each of which has basically the same structure as that shown in FIG. 10.
The structure shown in FIG. 10, however, has a disadvantage that since the terminal board 23 projects outwardly from the base 22, there is a fear that the terminal board 23 may be deformed only by applying a slight external force to the terminal board 23, resulting in a contact failure between the circuit board and the terminal board 23 due to bending of the terminal board 23 and disconnection of the winding terminal 21a.
FIG. 11 shows the structure of another related art inductance element, in which a terminal board 25 mounted on a base 24 is bent on a bottom surface 26 side of the base 24. Japanese Utility Model Publication No. Hei 2-14179 and Japanese Utility Model Laid-open No. Sho 60-74328 disclose inductance elements each of which has basically the same structure as that shown in FIG. 11. The inductance element having such a structure is advantageous in that since the terminal board 25 does not project outwardly from the base 24, it is possible to prevent occurrence of the above-described inconvenience that the terminal board 25 Is deformed when an external force is applied to the terminal board 25.
When the terminal board 25 is bent on the bottom surface 26 side of the base 24 in such a manner as to be brought into contact therewith as shown in FIG. 11, the terminal board 25 may spring downwardly out of the bottom surface 26 of the base 24, as shown by a dotted line in FIG. 11, by a so-called spring back caused by elasticity of the terminal board 25.
If there occurs such downward spring-out of the terminal board 25, it is impossible to fixedly support the inductance element at a horizontal position upon mounting the inductance element on a circuit board, and therefore, it is difficult to rigidly bond the terminal board 25 on a circuit pattern of the circuit board by soldering. Even when the base 24 is adhesively bonded to the circuit board, since the bottom surface 26 of the base 24 is floated from the surface of the circuit board, it is difficult to certainly, rigidly bond the base 24 to the circuit board, and at the worst case, the inductance element may be peeled from the surface of the circuit board.